Now that firefox is available in sisyphus_riscv64,
let's use it as our default browser.

Note that firefox-esr is not yet available, so now on
riscv64 firefox is selected for use/browser/firefox-esr.

Since, starting with the version of mkimage-profiles 1.4.21, enumeration of
architectures in lists is supported, it can be simplified.

...so it supports H.264 media; should be fixed
by making it use ffmpeg4 some day hopefully.

See-also: http://html5test.com
Reported-by: http://domination.one

Borrowed from workstation/the.pkgs.

See-also: 79d3ed53

This reverts commit bf762a26.
The issue on RPi3 is not observed with firefox-esr-78.9.0-alt0.1.p9

firefox not availability for armh and mipsel.

Firefox-esr segfaults on Rpi3 for unknown reason.

They are provided by firefox-esr itself now.

Seems it was removed from repository.
Another lang subpackages provided by firefox-esr now.

Seems firefox is faster as reported by jqt4@.